Secure cargo transportation system

ABSTRACT

A secure cargo transportation system includes a movable container including an enclosure having an opening; a door movable relative to the opening between a closed position, wherein the door restricts access to the enclosure, and an open position; a memory supported by the movable container and configured to store a location coordinate; and an electronic position determining system supported by the movable container and coupled to the memory, and configured to electronically unlock the door in response to determining that the movable container is within a predetermined distance of the location coordinate.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. patent application Ser. No. 09/516,634,filed Mar. 1, 2000 U.S. Pat. No. 6,583,713, which in turn is acontinuation of U.S. patent application Ser. No. 08/911,303, filed Aug.14, 1997, now U.S. Pat. No. 6,057,779, both of which are incorporatedherein by reference.

TECHNICAL FIELD

The invention relates to transportation systems. The invention alsorelates to security systems, lock systems, and access control.

BACKGROUND OF THE INVENTION

Valuable cargo is transported on a daily basis. It is desirable tosecure the cargo against unauthorized access, so as to preventtampering, theft of some cargo, or theft of all cargo.

Cargo is typically secured using conventional locks, such as padlocks,which are opened using a metal key. For example, for cargo transportedby semi-trailers, the cargo is typically secured by locking the trailerdoor with a padlock. The driver then carries the key.

A problem with conventional methods of securing cargo is that the driverhas access to the cargo and has the opportunity to steal some or all ofthe cargo. Further, there is the possibility of the driver beinghijacked, and the key taken from the driver. There is also thepossibility of the driver diverging from the intended course and takingthe cargo to a non-approved area, such as to a competitor, to anotherstate or country, or through an area where the risk of theft is greater.

SUMMARY OF THE INVENTION

The invention provides a method and system for controlling access to amovable container. The container is controllably locked using anelectronically actuated locking mechanism. The locking mechanism iscaused to unlock the container if a condition is met. The condition canbe based on geographical location, date or time, or an override if thegeographical location of the container cannot be determined. In oneembodiment, a desired geographical location is stored in memory, thegeographical location of the container is determined, and the lockingmechanism is caused to unlock the container if the determinedgeographical location matches the desired geographical location.

In one aspect of the invention, the global positioning system is incommunication with the memory and the locking mechanism.

In one aspect of the invention, the global positioning systemcommunicates with the locking mechanism via radio frequency to cause thelocking mechanism to unlock the container if the determined geographicallocation matches the desired geographical location. In another aspect ofthe invention, the global positioning system is electrically wired tothe locking mechanism.

In one aspect of the invention, the desired geographical location isreceived via wireless communication, such as via microwave.

In one aspect of the invention, a global positioning system is used todetermine the geographical location of the container. An area orgeographical location can be defined by specifying a point and radius ora series of points and with an offset.

For example, in one aspect of the invention, storing in memory a desiredgeographical location comprises storing coordinates of at least threegeographical points, and enabling the locking mechanism to unlock thecontainer if the determined geographical location matches the desiredgeographical location comprises enabling the locking mechanism to unlockthe container if the determined geographical location falls within anarea defined by the coordinates.

In one aspect of the invention, storing in memory a desired geographicallocation comprises storing data representing a point, and storing datarepresenting a radius, and enabling the locking mechanism to unlock thecontainer if the determined geographical location matches the desiredgeographical location comprises enabling the locking mechanism to unlockthe container if the determined geographical location falls within anarea defined within a radius about the point corresponding to the storedradius.

In one aspect of the invention, the determination of the geographicallocation is repeated multiple times.

Another aspect of the invention provides a method and system forcontrolling access to a compartment of a vehicle. An electronicallyactuated locking mechanism is used for locking the compartment. Aspecified geographical area is received via wireless communications. Thereceived geographical area is stored in memory. The geographicallocation of the vehicle is periodically determined using a globalpositioning system. Respective determined geographical locations arecompared with the stored geographical area to ascertain whether thevehicle is within the stored geographical area, and the electronicallyactuated locking mechanism is caused to unlock the compartment if it isdetermined that the vehicle is within the stored geographical area.

Another aspect of the invention provides a method and system forcontrolling access to a movable container using an electronicallyactuated locking mechanism to lock the container. A plurality ofgeographical areas through which it is desired that the container travelare stored in memory. The geographical location of the container at eachof a plurality of different times is logged, and the locking mechanismis caused to unlock the container if the container passed through eachof the geographical areas stored in memory.

In one aspect of the invention, an order of geographical areas isdefined, and the locking mechanism is caused to unlock the container ifthe container passed through each of the geographical areas in thedefined order.

In one aspect of the invention, an order of geographical areas isdefined, including a final destination geographical area, and thelocking mechanism is enabled to unlock the container if the containerpassed through each of the geographical areas in the defined order andis in the final destination geographical area.

In another aspect of the invention, data defining a desired path oftravel through which it is desired that the container travel is storedin memory. A geographical area defining a desired final destination isalso stored in memory. An alert signal is produced if the vehicledeviates from the desired path of travel. In one aspect of theinvention, data is stored defining a plurality of overlappinggeographical areas.

Another aspect of the invention provides a secure cargo transportationsystem. The secure cargo transportation system comprises a vehicleincluding an enclosure having an opening. A door is movable relative tothe opening between a closed position, wherein the door restricts accessto the enclosure, and an open position. An electronically actuable lockis configured to selectively lock or unlock the door relative to theenclosure. A memory is supported by the vehicle and configured to storea location coordinate, and a global positioning system is supported bythe vehicle and coupled to the memory and to the lock, and configured toenable the lock to unlock the door if the vehicle is within apredetermined distance of the location coordinate.

In one aspect of the invention, a remote intelligent communicationsdevice includes a global positioning system, is supported by a vehicleand is coupled to a lock. The wireless communications device includes amemory configured to store data representing a location, and the deviceenables the lock to unlock the door if the vehicle is within apredetermined distance of the location coordinate. The remoteintelligent communications device is configured to receive the data viawireless communications.

In one aspect of the invention, the remote intelligent communicationsdevice is configured to receive data at microwave frequencies.

In one aspect of the invention, the remote intelligent communicationsdevice includes indicia for uniquely identifying the vehicle withrespect to other vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a perspective view illustrating a secure cargo transportationsystem and a method for controlling access to a movable container.

FIG. 2 is a diagrammatical perspective view illustrating a lock,controller, and key included in the system of FIG. 1.

FIG. 3 is a block diagram illustrating the system of FIG. 1 incommunication with a central communications station.

FIG. 4 is a block diagram of an interrogator or transmitter included inthe central station of FIG. 3.

FIG. 5 is a block diagram showing details of DPSK circuitry included inthe interrogator of FIG. 4.

FIG. 6 is a block diagram showing details of RF circuitry included inthe interrogator of FIG. 4.

FIGS. 7 and 8 together define a flowchart illustrating operation of thesecure cargo transportation system of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

FIG. 1 shows a secure cargo transportation system 10 embodying theinvention. The secure cargo transportation system 10 comprises a movablecontainer or vehicle 12 including an enclosure 14 having an opening 16.In the illustrated embodiment, the vehicle 12 is a semi trailer. Inalternative embodiments, the movable container is defined by a trainboxcar, a safe, a compartment in a boat or plane, or any other movablecontainer. The vehicle 12 includes a door 18 movable relative to theopening 16 between a closed position, wherein the door 18 restrictsaccess to the enclosure, and an open position (FIG. 2). In someembodiments, the vehicle includes multiple doors 18, 20. The vehicle 12includes an electronically actuable lock 22 to selectively lock orunlock the door relative to the enclosure. In embodiments having twodoors, the primary door is locked with an electronically enabled oractuable lock 22, or both doors are locked with an electronicallyenabled or actuable lock 22 such that access to the enclosure requiresunlocking at least one electronically actuable lock 22.

More particularly, in the preferred embodiment, the doors 18 and 20 arefitted with an intelligent lock controller such as the lock controllersold by Intellikey Corporation, 551 S. Apollo Blvd., #204, Melbourne,Fla. 32901. In one embodiment, pre-existing mechanical cylinders can bereplaced with electronic cylinders of the type sold by Intellikey, orthe electronic cylinders can be installed initially. An electroniccontroller 24 is supported by the back of the door, inside the enclosure14, or in other appropriate (preferably secure) location. In theillustrated embodiment, the lock 22 requires both an electronic key orsignal and a mechanical key to open the lock. More particularly, a key26 has a mechanical portion 28 as well as circuitry 30 supportedtherefrom (e.g., in the handle for the key) which communicateselectronically with the lock (e.g., by radio frequency or magneticcoupling). In alternative embodiments, only an electronic key or signalis required to open the lock. Data communicated between the key and lockis encrypted, in the illustrated embodiment. In the illustratedembodiment, the key and lock provide multiple levels of access. Forexample, in the illustrated embodiment, seven masterkeying levels areavailable. The electronic controller 24 can be programmed to changewhose key will open the lock and when. The circuitry 30 of the key 26includes memory which carries access control information and identifyinginformation for the user of the key. The controller 24 reads thisinformation and determines whether the user of the key should be grantedaccess. The controller 24 is programmable to grant access to the user ofthe key based on factors such as location and time. The memory of thecircuitry 30 records an audit trail of in which lock the associated key26 has been used. In addition to the electronic controller 24 beingprogrammable, the circuitry 30 of the key 26 is also programmable, andaccess control and feature information can be changed for each key usinga key programming unit available from Intellikey Corporation.

The system 10 further includes a remote intelligent communicationsdevice 32 (FIG. 3) supported by the vehicle 12 and in communication withthe lock 29. More particularly, in the illustrated embodiment, theremote intelligent communications device 32 has an RS-232 port, andcommunicates with the lock controller 24 via a RS-232 cable connectedbetween the RS-232 port of the device 32 and the lock controller 24. Theremote intelligent communications device 32 includes a processor 33, amemory 34 coupled to the processor 33, and a global positioning systemreceiver 36 in communications with the processor 33, and thus with thememory 34. The global positioning system receiver 36 communicates with aglobal positioning satellite 37 to determine the position of thereceiver 36. While other embodiments are possible, in the illustratedembodiment, the global positioning system receiver 36 is an Encore (TM)GPS receiver manufactured by or available from Motorola Inc.,Schaumburg, Ill. The remote intelligent communications device 32periodically or at various times logs in the memory 34 the position ofthe device 32 (and therefore the position of the vehicle 12) withrespect to time. The remote intelligent communications device 32 usesUTC time obtained from GPS satellite data to provide time of dayinformation for use with the logging of the position information.

An exemplary remote intelligent communications device 32 that can beemployed is described in commonly assigned U.S. patent application Ser.No. 08/656,530, titled “A Method And Apparatus For Remote Monitoring,”incorporated herein by reference. In the preferred embodiment, theremote intelligent communications device 32 is an Ambit (TM) remoteintelligent communications device available from Micron Communications,Boise, Id. The Ambit (TM) device is a board level device which issimilar in design and operation to an integrated circuit described incommonly assigned U.S. patent application Ser. No. 08/705,043, filedAug. 29, 1996 and incorporated herein by reference, except that itfurther includes the global positioning system receiver.

The remote intelligent communications device 32 further includes a radiofrequency (RF) communications receiver 38 coupled to the processor 33,which receives a desired location coordinate at which access to thecontents of the enclosure 14 is permitted. The remote intelligentcommunications device 32 further includes a radio frequency (RF)communications transmitter 39 coupled to the processor 33. In theillustrated embodiment, the remote intelligent communications devicereceives and transmits data at microwave frequencies. The remoteintelligent communications device includes indicia for uniquelyidentifying the vehicle 12 with respect to other vehicles 12. A centralstation 46 can communicate with a specified vehicle 12 out of a fleet ofvehicles 12, 12 b. More particularly, in the illustrated embodiment,multiple vehicles are equipped with the remote intelligentcommunications device 32 and lock 22, and the central station 46 cancommunicate with any desired vehicles to control access to enclosure 14of a specified vehicle.

Desired access locations, such as docking bays 42 at final destinationsare determined by a responsible person 44 at a central station 46 andcommunicated to the vehicle 12, such as by using a transmitter 49(described below) located at or controlled at the central station 46.

When the vehicle 12 enters into a specified area as determined by theGPS receiver 36, the remote intelligent communications device 32 sends adigital message to the controller 24 enabling the lock 22 to be openedwith the key 26. The GPS area is defined so as to take into account theerror possible with the GPS receiver 36 being used. The receiver 38receives commands from the transmitter 49 when in communications rangewith a transmitter.

A desired or specified location 48 received by the receiver 38 is storedin memory. For example, the receiver receives a point and a radius, orthree geographic points to define a desired area or location, or twopoints to define a line and an offset distance to the left and right ofthe line. In one embodiment, the processor 33 provides a signal to thecontroller 24 of the lock to enable unlocking using the key 26 if thevehicle 12 is within a predetermined distance of the desired location.Multiple locations can be specified where access is permitted. Inanother embodiment, the processor 33 provides for exception logic,enabling unlocking in all areas except a specified location 48.

Other methods of receiving and storing location coordinates can beemployed. For example, some coordinates can be pre-programmed. Forexample, weigh stations at state lines have known coordinates which canbe stored in memory so unlocking is enabled at these locations.

Further, new location coordinates where access is permitted can becommunicated to the device 32 by a paging network or system 50. To thisend, the device 32 further includes a paging receiver 52 coupled to theprocessor 33. Emergency access to the contents of the enclosure 14 canbe granted by the operator 44 using the paging system. For example, ifthe vehicle is stopped by police who want to inspect cargo in theenclosure 14, the driver of the vehicle, using a telephone 54, can calla telephone 56 manned by the operator 44 at the central station 46. Theoperator 44 can then authorize access, regardless of the vehicle'slocation, using the same or a different telephone 58 to access thepaging system 50. The telephone 54 used by the driver can be a cellularphone on board the vehicle, or a pay phone or other phone locatedoutside the vehicle 12.

Alternatively, a cellular receiver can be employed instead of the pagingreceiver.

In one embodiment, a plurality of geographical areas 60 through which itis desired that the vehicle 12 travel are stored in memory 34. Thegeographical location of the container at each of a plurality ofdifferent times is logged, and the locking mechanism 22 is enabled topermit unlocking if the vehicle 12 passed through all of thegeographical areas stored in memory 34.

In another embodiment of the invention, an order of geographical areasis defined, and the locking mechanism 22 is enabled to permit unlockingif the vehicle passed through the geographical areas in the definedorder.

In another embodiment, an order of geographical areas is defined,including a final destination geographical area (e.g., area 48), and thelocking mechanism 22 is enabled to unlock if the vehicle 12 passedthrough each of the geographical areas 60 in the defined order and is inthe final destination geographical area.

In another embodiment of the invention, data defining a desired path oftravel through which it is desired that the container travel is storedin memory 34. A geographical area defining a desired final destination(e.g., area 48) is also stored in memory 34. An alert signal is producedif the vehicle 12 deviates from the desired path of travel. In oneaspect of the invention, data is stored defining a plurality ofoverlapping geographical areas. In one embodiment, the device 32 iscoupled to the electrical system of the vehicle 12, or to an enginecontroller of the vehicle 12, and cuts off the engine if the vehicledeviates from the desired path of travel by more than a programmedamount. For example, the device 32 can be coupled to the enginecontroller in the manner disclosed in commonly assigned U.S. patentapplication Ser. No. 08/759,737, filed Dec. 6, 1996 and incorporatedherein by reference.

As previously mentioned, the central station 46 includes the transmitter49. More particularly, in the illustrated embodiment, the centralstation 46 includes an interrogator 47 comprising the transmitter 49,and further comprising a receiver 51. The remote intelligentcommunications device 32 transmits and receives radio frequencycommunications to and from the interrogator 47. The central station 46further includes one or more send/receive antenna pairs 62 coupled tothe interrogator 47. In an alternative embodiment, the interrogator 47uses an antenna both for transmitting and receiving by the interrogator47. The interrogator 47 includes transmitting and receiving circuitry,similar to that implemented in the remote intelligent communicationdevice 32. In one embodiment, the system central station 46 furtherincludes a controller 64. In the illustrated embodiment, the controller64 is a computer. The controller 64 acts as a master in a master-slaverelationship with the interrogator 47. The controller 64 includes anapplications program for controlling the interrogator 47 andinterpreting responses, and a library of radio frequency identificationdevice applications or functions as described in the above-incorporatedpatent applications. Most of the functions communicate with theinterrogator 47. These functions effect radio frequency communicationbetween the interrogator 47 and the remote intelligent communicationsdevice 32. In one embodiment, the controller 64 and the interrogator 47are combined together (e.g., in a common housing), or functions of thehost computer are implemented in hard wired digital logic circuitry.

Generally, the interrogator 47 transmits an interrogation signal orcommand, such as a command to add geographical locations where openingof the lock 22 is enabled, (“forward link”) via one of the antennas 62.The remote intelligent communications device 32 receives the incominginterrogation signal via its antenna, if it is within receiving range.Upon receiving the signal, the remote intelligent communications device32 responds by generating and transmitting a responsive signal or reply(“return link”). The interrogator 47 is described in greater detailbelow.

In the illustrated embodiment, signals transmitted and received by theinterrogator 47, and signals transmitted and received by the remoteintelligent communications device 32 are modulated spread spectrumsignals. Many modulation techniques minimize required transmissionbandwidth. However, the spread spectrum modulation technique employed inthe illustrated embodiment requires a transmission bandwidth that is upto several orders of magnitude greater than the minimum required signalbandwidth. Although spread spectrum modulation techniques are bandwidthinefficient in single user applications, they are advantageous wherethere are multiple users (e.g., multiple vehicles 12, 12 b). The spreadspectrum modulation technique of the illustrated embodiment isadvantageous because the interrogator signal can be distinguished fromother signals (e.g., radar, microwave ovens, etc.) operating at the samefrequency. The spread spectrum signals transmitted by the device 32 andby the interrogator 47 are pseudo random and have noise-like properties.A spreading waveform is controlled by a pseudo-noise or pseudo randomnumber (PN) sequence or code. The PN code is a binary sequence thatappears random but can be reproduced in a predetermined manner by thedevice 32. More particularly, incoming spread spectrum received by thedevice 32 or interrogator 47 are demodulated through cross correlationwith a version of the pseudo random carrier that is generated by thedevice 32 itself or the interrogator 47 itself, respectfully. Crosscorrelation with the correct PN sequence unspreads the spread spectrumsignal and restores the modulated message in the same narrow band as theoriginal data.

A pseudo-noise or pseudo random sequence (PN sequence) is a binarysequence with an autocorrelation that resembles, over a period, theautocorrelation of a random binary sequence. The autocorrelation of apseudo-noise sequence also roughly resembles the autocorrelation ofband-limited white noise. A pseudo-noise sequence has manycharacteristics that are similar to those of random binary sequences.For example, a pseudo-noise sequence has a nearly equal number of zerosand ones, very low correlation between shifted versions of the sequence,and very low cross correlation between any two sequences. A pseudo-noisesequence is usually generated using sequential logic circuits. Forexample, a pseudo-noise sequence can be generated using a feedback shiftregister.

A feedback shift register comprises consecutive stages of two statememory devices, and feedback logic. Binary sequences are shifted throughthe shift registers in response to clock pulses, and the output of thevarious stages are logically combined and fed back as the input to thefirst stage. The initial contents of the memory stages and the feedbacklogic circuit determine the successive contents of the memory.

The illustrated embodiment employs direct sequence spread spectrummodulation. A direct sequence spread spectrum (DSSS) system spreads thebaseband data by directly multiplying the baseband data pulses with apseudo-noise sequence that is produced by a pseudo-noise generator. Asingle pulse or symbol of the PN waveform is called a “chip.”Synchronized data symbols, which may be information bits or binarychannel code symbols, are added in modulo-2 fashion to the chips beforebeing modulated. The receiver performs demodulation. For example, in oneembodiment the data is phase modulated, and the receiver performscoherent or differentially coherent phase-shift keying (PSK)demodulation. In another embodiment, the data is amplitude modulated.Assuming that code synchronization has been achieved at the receiver,the received signal passes through a wideband filter and is multipliedby a local replica of the PN code sequence. This multiplication yieldsthe unspread signal. A pseudo-noise sequence is usually an odd number ofchips long.

Spread spectrum techniques are also disclosed in the following patentapplications and patent, which are incorporated herein by reference:U.S. patent application Ser. No. 08/092,147; U.S. patent applicationSer. No. 08/424,827, filed Apr. 19, 1995; and U.S. Pat. No. 5,121,407 toPartyka et al. They are also disclosed, for example, in “Spread SpectrumSystems,” by R. C. Dixon, published by John Wiley and Sons. Inc.

In one embodiment, the interrogator 47 is coupled to the controller 64via an IEEE-1284 enhanced parallel port (EPP).

In one embodiment, communications from the interrogator 47 to the device32, and communications from the device 32 to the interrogator 47 usedifferent physical protocols.

The physical communications protocol for communications from theinterrogator 47 to the device 32 is referred to as the “forward link”protocol. In the illustrated embodiment, the forward link data is sentin the following order:

Preamble

Barker Code

Command Packet

Check Sum

A Maximal Length Pseudo Noise (PN) Sequence is used in the DirectSequence Spread Spectrum (DSSS) communications scheme in the forwardlink. In one embodiment, the sequence is generated by a linear feedbackshift register of a specified form. In the illustrated embodiment, thereare multiple registers, the output of one of the registers is X-ORedwith the output of another register, and the result is fed into theinput of the first register. This produces a repeating 31 “chip”sequence. The sequence ends with all registers set to one. The sequenceis taken from the output of the first register. This code is synchronouswith the data in that each data bit comprises one and only one full PNsequence.

In one embodiment, a zero bit is transmitted as one inverted full cycleof the PN sequence. A one bit is transmitted as one full non-invertedcycle of the PN sequence.

The preamble precedes the data. In one embodiment, the preamble includesa series of zeros, followed by a start or Barker code.

In one embodiment, the Barker code is defined by the following bitstring: 1111 1001 1010 1. Other embodiments are of course possible.

In the illustrated embodiment, command data is grouped into 13-bitwords. Each word includes eight data bits (D7, D6, D5, D4, D3, D2, D1,D0) and five ECC (Error Correction Code) bits (P4, P3, P2, P1, and P0).In one embodiment, the bit transmission order is (with D7 transmittedfirst):

D7, D6, D5, D4, D3, D2, D1, D0, P4, P3, P2, P1, P0 . . . .

In one embodiment, the ECC bits (P4-P0) are generated using thefollowing equations:

P0=(D1+D2+D5+D7)modulo 2

P1=[(D1+D3+D4+D6)modulo 2] Complement

P2=(D0+D2+D3+D6+D7)modulo 2

P3=[(D0+D4+D5+D6+D7)modulo 2] Complement

P4=(D0+D1+D2+D3+D4+D5)modulo 2.

Other methods of generating the error correction code bits are of coursepossible.

In the illustrated embodiment, a 16-bit check sum is provided to detectbit errors on the packet level. The device 32 can be programmed toeither return a reply if a bad check sum is found in the forward link,or to simply halt execution and send no replies. In one embodiment, a 16bit CRC is employed in the forward link, the return link, or both,instead of or in addition to the check sum.

The physical communications protocol for communications from the device32 to the interrogator 47 is referred to as the “return link” protocol.In the illustrated embodiment, the return link messages are sent in thefollowing order:

Preamble,

Barker Code,

Reply Packet

Check Sum

After sending a command, the interrogator 47 sends a continuousunmodulated RF signal with a specified frequency, such as 2.44 GHz, 915MHz, or other frequencies. In the illustrated embodiment, return linkdata is Differential Phase Shift Key (DPSK) modulated onto a square wavesubcarrier with a frequency of 596.1 kHz. A data 0 corresponds to onephase and data 1 corresponds to another, shifted 180 degrees from thefirst phase. For a simple dipole, a switch between the two halves of thedipole antenna is opened and closed. When the switch is closed, theantenna becomes the electrical equivalent of a single half-wavelengthantenna that reflects a portion of the power being transmitted by theinterrogator. When the switch is open, the antenna becomes theelectrical equivalent of two quarter-wavelength antennas that reflectvery little of the power transmitted by the interrogator.

The preamble for the return link includes 2000 bits, alternating 2 zerosthen 2 ones, etc., and a 13-bit start (Barker) code. Alternativepreambles are possible.

In the illustrated embodiment, the start code or Barker Code is definedby the following bit string: 1111 1001 1010 1.

The reply link data is grouped in 13 bit words. Each word is composed of8 data bits (D7, D6, D5, D4, D3, D2, D1, D0) and 5 ECC bits (P4, P3, P2,P1, P0).

The Block Encoded Sequence is D7, D6, D5, D4, D3, D2, D1, D0, P4, P3,P2, P1, P0.

The Block ECC Bits (P4-P0) are generated using the following equations:

P0=(D1+D2+D5+D7)modulo 2

P1=[(D1+D3+D4+D6)modulo 2] Complement

P2=(D0+D2+D3+D6+D7)modulo 2

P3=[(D0+D4+D5+D6+D7)modulo 2] Complement

P4=(D0+D1+D2+D3+D4+D5)modulo 2.

Other methods of generating error correction code bits can, of course,be employed.

In the illustrated embodiment, a 16-bit check sum is provided to detectbit errors on the packet level. In one embodiment, a 16 bit CRC isemployed in addition to or instead of the check sum.

Each pair of data words is interleaved, starting with the Barker codeand the first data word. The transmitted bit order for two sequentialwords, A and B, is D7A, D7B, D6A, D6B, D5A, D5B, D4A, D4B, D3A, D3B,D2A, D2B, D1A, D1B, D0A, D0B, P4A, P4B, P3A, P3B, P2A, P2B, P1A, P1B,P0A, P0B.

D7A is the first transmitted bit. In the illustrated embodiment, DPSK isapplied to the interleaved data.

Other communications protocols are of course possible for the forwardlink and return link.

Details of construction of the interrogator 47 will now be provided,reference being made to FIG. 4. The interrogator 47 includes enhancedparallel port (EPP) circuitry 70, DPSK (differential phase shift keyed)circuitry 72, and RF (radio frequency) circuitry 74, as well as a powersupply (not shown) and a housing or chassis (not shown). In theillustrated embodiment, the enhanced parallel port circuitry 70, theDPSK circuitry 72, and the RF circuitry 74 respectively define circuitcard assemblies (CCAs). The interrogator 47 uses an IEEE-1284 compatibleport in EPP mode to communicate with the controller 64. The EPPcircuitry 70 provides all the digital logic required to coordinatesending and receiving a message to and from a remote intelligentcommunications device 32 of a vehicle 12. The EPP circuitry 70 buffersdata to transmit from the controller 64, converts the data to serialdata, and encodes it. The EPP circuitry 70 then waits for data from thedevice 32, converts it to parallel data, and transfers it to thecontroller 64. In one embodiment, messages include a programmable numberof bytes of data.

The EPP mode interface provides an asynchronous, interlocked, byte wide,bi-directional channel controlled by the controller 64. The EPP modeallows the controller 64 to transfer, at high speed, a data byte to/fromthe interrogator within a single host computer CPU I/O cycle (typically0.5 microseconds per byte).

The DPSK circuitry 72 (see FIG. 5) receives signals I and Q from the RFcircuitry 74 (described below), which signals contain the DPSK modulatedsub-carrier. The DPSK circuitry 72 includes anti-aliasing filters 76 and78 filtering the I and Q signals, respectively, and analog to digital(A/D) converters 80 and 82 respectively coupled to the filters 76 and 78and respectively converting the filtered signals from analog to digitalsignals. The DPSK circuitry 72 further includes a combiner 84, coupledto the A/D converters 80 and 82, combining the digital signals. The DPSKcircuitry 72 further includes a FIR matched filter 86, coupled to thecombiner 84, which filters the combined signals. The DPSK circuitry 72further includes delay circuitry 88 and multiplier circuitry 90 coupledto the FIR matched filter 86 for delaying the signal and multiplying thesignal with the delayed signal to remove the sub-carrier. The DPSKcircuitry 72 further includes low pass filter circuitry 92, coupled tothe multiplier 90, filtering the output of the multiplier 90 to removethe X2 component. The DPSK circuitry 72 further includes a bitsynchronizer 94 coupled to the filter 92 for regeneration of the dataclock. The DPSK circuitry 72 further includes lock detect circuitry 96coupled to the low pass filter 92 and generating a lock detect signal.The data, clock, and lock detect signal are sent to the EPP circuitry70.

The RF circuitry 74 (see FIG. 6) interfaces with the transmit andreceive antennas 62. The RF circuitry modulates the data fortransmission to a device 32 of a vehicle 12, provides a continuous wave(CW) carrier for backscatter communications with a device 32 (ifbackscatter communications are employed), and receives and downconvertsthe signal received from the transponder unit (which is a backscattersignal in one embodiment).

The RF circuitry 74 also includes a power divider 98, and a frequencysynthesizer 100 coupled to the power divider 98. The frequencysynthesizer 100 tunes the RF continuous waver carrier for frequencyhopping and band selection. The RF circuitry defines a transmitter, andreceives data from the EPP circuitry 70. The RF circuitry 74 includes anamplitude modulation (AM) switch 102 that receives the data from the EPPcircuitry 70 and amplitude modulates the data onto a carrier. Moreparticularly, the AM switch 102 turns the RF on and off (ON OFF KEY).The RF circuitry 74 further includes a power amplifier 104, coupled tothe AM switch 102, to amplify the signal. The RF circuitry 74 furtherincludes a switch 106, coupled to the power amplifier 104, fortransmission of the amplified signal through a selected transmit antenna62.

During continuous wave (CW) transmission for the backscatter mode, theAM switch 102 is left in a closed position. When the interrogator 50 istransmitting in the CW mode, the device 32 backscatters the signal witha DPSK modulated sub carrier. This signal is received via one of thereceive antennas 62. More particularly, the RF circuitry 74 furtherincludes a switch 108 coupled to the receive antennas. In anotheralternative embodiment, such as when backscatter communications are notemployed, the RF circuitry uses common antennas for both transmissionand reception. The RF circuitry 74 further includes a low noiseamplifier (LNA) 110 coupled to the switch 108 and amplifying thereceived signal. The RF circuitry 74 further includes a quadraturedownconverter 112, coupled to the LNA 110, coherently downconverting thereceived signal. The RF circuitry 74 further includes automatic gaincontrols (AGCs) 114 and 116 coupled to the quadrature down converter112. The amplitude of the signals are set using the automatic gaincontrols 114 and 116 to provide the signals I and Q. The I and Qsignals, which contain the DPSK modulated sub-carrier, are passed on tothe DPSK circuitry 72 (FIG. 5) for demodulation.

Although one interrogator 47 has been described, it may be desirable toprovide multiple interrogators along a route, or interrogators at eachof various facilities.

In one embodiment, communications between the central station 46 and adevice 32 may be via the paging system 50 and paging receiver 52 or viathe cellular system when the vehicle 12 is not within communicationsrange of an interrogator 47.

FIGS. 7 and 8 together define a flowchart illustrating operation of thesecure cargo transportation system.

In a step 120, a determination is made (e.g., by the processor 33 of theremote intelligent communications device 32) as to whether a command hasbeen received (e.g., from an interrogator 47 or paging receiver 52) toadd desired geographical areas. If so, the processor proceeds to step122; if not, the processor proceeds to step 128.

In step 122, a desired geographical area (e.g., a point and a radius, orthree or more points) is received by the device 32. After performingstep 122, the processor proceeds to step 124.

In step 124, the desired geographical areas are stored in memory 34.After performing step 124, the processor proceeds to step 126.

In step 126, a determination is made as to whether there are additionaldesired geographical areas to be stored in memory. If so, the processorproceeds to step 122; if not, the processor proceeds to step 128.

In step 128, a determination is made as to whether a command has beenreceived to change geographical areas. If so, the processor proceeds tostep 130; if not, the processor proceeds to step 136.

In step 130, the desired change is received. After performing step 130,the processor proceeds to step 132.

In step 132, the processor accesses the memory location of thegeographic area which is to be changed (or deleted). After performingstep 132, the processor proceeds to step 134.

In step 134, the processor changes (or deletes) data in the accessedmemory location, as desired. After performing step 134, the processorproceeds to step 136.

In step 136, a determination is made as to whether a command has beenreceived to change a user's ability to access the container or vehicle12. If so, the processor proceeds to step 138; if not, the processorproceeds to step 140.

In step 138, the device 32 communicates with the lock controller tochange a user's ability to access the container. After performing step138, the processor proceeds to step 140.

In step 140, the present location of the container is logged using theGPS receiver 36. After performing step 140, the processor proceeds tostep 142.

In step 142, a determination is made as to whether the vehicle 12 orcontainer is off course. If so, the processor proceeds to step 144; ifnot, the processor proceeds to step 146.

In step 144, an alarm signal is sent (e.g., an audible or, visible alarmis sent to the driver and/or to the central station 46). Afterperforming step 144, the processor proceeds to step 146.

In step 146, a determination is made as to whether the vehicle orcontainer is in a desired geographical area (e.g., the desired finaldestination area). If so, the processor proceeds to step 148; if not,the processor proceeds to step 150.

In step 148, a determination is made as to whether other requirementsfor access are met (e.g., the vehicle or container is in the desiredgeographic area at a specified time; the vehicle passed through aspecified sequence of desired areas; the holder of the key 26 is aperson authorized to open the lock in this area and at this time; anyother conditions imposed by the central station 46). After performingstep 148, the processor proceeds to step 152.

In step 150, a determination is made as to whether an overrideauthorization has been received from the central station 46 (e.g., thevehicle is not in the desired area, but there is an emergencysituation). If so, the processor proceeds to step 152; if not, theprocessor proceeds to step 120 (possibly after a time delay).

In step 152, the device 32 sends a signal to the lock 22 enabling thelock to be opened (e.g., effecting unlocking, or permitting unlockingusing the key 26).

Thus, a method of controlling access to a movable container is provided.As a mobile asset, such as a container, truck or some other thingtravels, its movement is recorded into the memory of the device, withthe location and movement being determined by GPS.

The location of the vehicle will be utilized to determine authorizationkeyed access to a truck. The keyed system, as tied into the GPS, wouldbe such that opening would be authorized when the vehicle is within theconfines of a specific location. Further, different parts of the vehicleor container may be subjected to different keyed openings, such thatsome enclosure of the vehicle can be opened at one location, but notothers.

In one embodiment, the system is programmed in a “fail safe” manner, forexample tieing the ultimate access to some specific route over which thevehicle is expected to travel. Therefore if the truck is hijacked or thedriver deviates from a prescribed course, no opening whatsoever of thevehicle would be allowed, absent obtaining some authorization or someother code. In other words, the proximity within a desired route andending locations can be programmed into the device.

In one embodiment, when the container, truck, etc. moves in theproximity of some general RF station, the data from the memory isdownloaded or transmitted via RF to the base unit, such that theinformation is obtained and recorded remotely of the AMBIT unit on thevehicle.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

What is claimed is:
 1. A secure cargo transportation system comprising:a movable container including an enclosure having an opening; a doormovable relative to the opening between a closed position, wherein thedoor restricts access to the enclosure, and an open position; a memorysupported by the movable container and configured to store a locationcoordinate; an electronic position-determining system, supported by themovable container and coupled to the memory and configured toelectronically unlock the door in response to determining that themovable container is within a predetermined distance of the locationcoordinate; and a wireless receiver supported by the movable containerand coupled to the memory and configured to transfer to the memory alocation coordinate received from a remote transmitter.
 2. A system inaccordance with claim 1, further comprising an electronically actuablelock coupled to the door and responsive to the electronicposition-determining system.
 3. A system in accordance with claim 1,wherein the electronic position-determining system includes the memory.4. A system in accordance with claim 1, wherein the electronicposition-determining system communicates with the lock via radiofrequency to enable the lock to unlock the door in response todetermining that the movable container is within a predetermineddistance of the location coordinate.
 5. A system in accordance withclaim 1, wherein the electronic position-determining system iselectrically hardwired to the lock.
 6. A system in accordance with claim1, further comprising a microwave receiver supported by the movablecontainer, coupled to the memory and configured to transfer to thememory a location coordinate received via microwave from a microwavetransmitter.
 7. A system in accordance with claim 1, wherein theelectronic position-determining system comprises a processor configuredto determine when the movable container is within a predetermineddistance of the location coordinate.
 8. A system in accordance withclaim 1, further comprising an electronically actuable lock configuredto selectively lock or unlock the door relative to the enclosure.
 9. Asystem in accordance with claim 8, wherein the electronically actuablelock is configured to be actuable in response to a digital key.
 10. Asecure cargo transportation system comprising: a movable containerincluding an enclosure having an opening; a door movable relative to theopening between a closed position, wherein the door restricts access tothe enclosure, and an open position; an electronic position-determiningsystem, supported by the movable container and including a memoryconfigured to store a location coordinate, the electronicposition-determining system being configured to selectively lock andunlock the door relative to the enclosure, and to unlock the door whenthe movable container is within a predetermined distance of the locationcoordinate; and a wireless receiver supported by the movable containerand coupled to the memory and configured to transfer to the memory alocation coordinate received from a transmitter.
 11. A system inaccordance with claim 10 wherein the electronic position-determiningsystem communicates with a locking mechanism configured to selectivelylock and unlock the door relative to the enclosure via radio frequencycommands, the electronic position-determining system being configured toenable the lock to unlock the door when the movable container is withina predetermined distance of the location coordinate.
 12. A system inaccordance with claim 10 wherein the electronic position-determiningsystem is hardwired to the locking mechanism.
 13. A system in accordancewith claim 10, wherein the receiver is a microwave receiver configuredto receive data transmitted at microwave frequencies.
 14. A system inaccordance with claim 10, wherein the electronic position-determiningsystem comprises a processor configured to enable the lock to unlock thedoor when the movable container is within a predetermined distance ofthe location coordinate.
 15. A secure cargo transportation systemcomprising: a movable container including an enclosure having anopening; a door movable relative to the opening between a closedposition, wherein the door restricts access to the enclosure, and anopen position; and a remote intelligent communications device includingan electronic position-determining system, supported by the movablecontainer and coupled to the door, the remote intelligent communicationsdevice including a memory configured to store data representing alocation, the remote intelligent communications device enablingunlocking of the door when the movable container is within apredetermined distance of the location coordinate, the remoteintelligent communications device being configured to receive the datavia wireless communications.
 16. A secure cargo transportation system inaccordance with claim 15, wherein the remote intelligent communicationsdevice is configured to receive data at microwave frequencies.
 17. Asecure cargo transportation system in accordance with claim 15, whereinthe enclosure is defined by a semi trailer.
 18. A secure cargotransportation system in accordance with claim 15, wherein the remoteintelligent communications device includes indicia for uniquelyidentifying the movable container with respect to other movablecontainers.
 19. A secure cargo transportation system in accordance withclaim 15, further comprising an electronically actuable lock configuredto selectively lock or unlock the door relative to the enclosure inresponse to commands from the device.
 20. A secure cargo transportationsystem comprising: a movable container including an enclosure having anopening; a door movable relative to the opening between a closedposition, wherein the door restricts access to the enclosure, and anopen position; a memory supported to move with the movable container andconfigured to store a location coordinate; an electronicposition-determining system, supported to move with the movablecontainer and coupled to the memory and configured to electronicallyunlock the door in response to determining that the movable container iswithin a predetermined distance of the location coordinate; and awireless receiver supported to move with the movable container andcoupled to the memory and configured to transfer to the memory alocation coordinate received from a remote transmitter.
 21. A system inaccordance with claim 20, further comprising an electronically actuablelock coupled to the door and responsive to the electronicposition-determining system.
 22. A system in accordance with claim 20,wherein the electronic position-determining system includes the memory.23. A system in accordance with claim 20, wherein the electronicposition-determining system communicates with the lock via radiofrequency to enable the lock to unlock the door in response todetermining that the movable container is within a predetermineddistance of the location coordinate.
 24. A system in accordance withclaim 20, wherein the electronic position-determining system iselectrically hardwired to the look.
 25. A system in accordance withclaim 20, further comprising a microwave receiver supported by themovable container, coupled to the memory and configured to transfer tothe memory a location coordinate received via microwave from a microwavetransmitter.
 26. A system in accordance with claim 20, wherein theelectronic position-determining system comprises a processor configuredto determine when the movable container is within a predetermineddistance of the location coordinate.
 27. A system in accordance withclaim 20, further comprising an electronically actuable lock configuredto selectively lock or unlock the door relative to the enclosure.
 28. Asystem in accordance with claim 27, wherein the electronically actuablelock is configured to be actuable in response to a digital key.
 29. Asecure cargo transportation system comprising: a movable containerincluding an enclosure having an opening; a door movable relative to theopening between a closed position, wherein the door restricts access tothe enclosure, and an open position; an electronic position-determiningsystem, supported to move with the movable container and including amemory configured to store a location coordinate, the electronicposition-determining system being configured to selectively lock andunlock the door relative to the enclosure, and to unlock the door whenthe movable container is within a predetermined distance of the locationcoordinate; and a wireless receiver supported to move with the movablecontainer and coupled to the memory and configured to transfer to thememory a location coordinate received from a transmitter.
 30. A systemin accordance with claim 29 wherein the electronic position-determiningsystem communicates with a locking mechanism configured to selectivelylock and unlock the door relative to the enclosure via radio frequencycommands, the electronic position-determining system being configured toenable the lock to unlock the door when the movable container is withina predetermined distance of the location coordinate.
 31. A system inaccordance with claim 29, wherein the electronic position-determiningsystem is hardwired to the locking mechanism.
 32. A system in accordancewith claim 29, wherein the receiver is a microwave receiver configuredto receive data transmitted at microwave frequencies.
 33. A system inaccordance with claim 29, wherein the electronic position-determiningsystem comprises a processor configured to enable the look to unlock thedoor when the movable container is within a predetermined distance ofthe location coordinate.
 34. A secure cargo transportation systemcomprising: a movable container including an enclosure having anopening; a door movable relative to the opening between a closedposition, wherein the door restricts access to the enclosure, and anopen position; and a remote intelligent communications device includingan electronic position-determining system, supported to move with themovable container and coupled to the door, the remote intelligentcommunications device including a memory configured to store datarepresenting a location, the remote intelligent communications deviceenabling unlocking of the door when the movable container is within apredetermined distance of the location coordinate, the remoteintelligent communications device being configured to receive the datavia wireless communications.
 35. A secure cargo transportation system inaccordance with claim 34, wherein the remote intelligent communicationsdevice is configured to receive data at microwave frequencies.
 36. Asecure cargo transportation system in accordance with claim 34, whereinthe enclosure is defined by a semi trailer.
 37. A secure cargotransportation system in accordance with claim 34, wherein the remoteintelligent communications device includes indicia for uniquelyidentifying the movable container with respect to other movablecontainers.
 38. A secure cargo transportation system in accordance withclaim 34, further comprising an electronically actuable lock configuredto selectively lock or unlock the door relative to the enclosure inresponse to commands from the device.